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Sunday, September 9, 2012

Overseeding Bermudagrass With a Winter Grass

Q. My backyard has a bermudagrass lawn and I would like to overseed with a winter ryegrass seed. When I have done this before, I "burned out" the bermuda by not watering it, then rented a power rake to de-thatch it. This year with all the rain, my bermuda is not turning brown. My concern is if the lawn is green the power rake will not remove the thatch. Also, which do you recommend annual or perennial rye seed and why?
Dethatcher or verical mower.

A. Overseeding bermudagrass with a cool season grass like one of the ryegrasses has a window of time which is optimum in the fall. This window is from September 15 to October 15. If you overseed to early, the bermudagrass is too active and will compete with your winter lawn. If you overseed too late, you run the risk that it will get too cold quickly and the overseeded grass may not all germinate and fill in your overseeded area.

            The mantra for effective overseeding is having “good soil to seed contact”. In other words, the seed should rest on the soil when you overseed correctly. If the bermudagrass is too dense, much of the seed will not land on the soil and you will have a spotty winter lawn.

Common Bermudagrass stolon
            Sounds like you have the correct sequence for overseeding; time the overseed around October 1, September 15 turn off the water to the bermudagrass, September 21 mow as short as possible (rotary mower on the lowest setting is fine), power rake or dethatch until you see bare soil, apply seed, fertilizer, topdress the seed and fertilizer and water.

            Bermudagrass lawns are usually mowed somewhere from ½ to 1 inch high. I like to let it grow to an 1½ in August/September. This produces more stem so I can “scalp” it better and get the seed to fall onto the soil for that good soil/seed contact.

            You can use annual ryegrass if you want but it is coarse textured, light green and rough to the touch. Perennial ryegrass is a much prettier grass and soft to the touch. You can put all the nitrogen you want on annual ryegrass and it will just not get the same dark green color as perennial ryegrass. It is more expensive but will give you a much prettier lawn.

Vine in Lawn Turns Out To Be Bermudagrass

Q. I found this vine growing in my lawn and sent you pictures of it.  I tried treating it with Ortho's Weed Be Gone.  As of this morning I still have the vine.  Do you have any idea what it may be and how I can treat it or get rid of it?
Vine in lawn appears to be bermudagrass
or Devil grass.

A. From the look of this "vine", it appears to be bermudagrass. Some old timers call it Devil grass mostly because it is the devil to get rid of. Once it is in a lawn, it is tough to nearly impossible to get rid of.

            It is easier to get rid of if it is in a shrub bed. Then you can cut it back to a foot long (as long as it has leaves) and "spot spray" what’s left with Roundup. Other products that have reasonable success at some control include Poast and Fusilade which can be used fairly safely among shrubs and groundcovers.

            Bermudagrass gets in a lawn usually if the lawn begins to "thin" or lose its density. This is because it is not kept full and dense. This can be because it is not fertilized regularly, mowed too short or an insect or disease problem.

            Mowing too short can occur by lowering your mower too close to the ground or by using a line trimmer and whacking the grass low around sprinkler heads or along the edge of the lawn to make it look pretty.

            The best defense is a good offense. Keep the lawn at 2 to 2 1/2 inches if it is fescue. Keep it fertilized regularly. If patches of the lawn die, do not disturb the dead area and/or reseed or resod until mid to late September when bermudagrass is going to sleep.

Bay Leaves Browning and Yellowing

Q. I have several bay leaf bushes but one appears to be dying.  What can I do, if anything, to nurse it back to health?

A. Two things are going to be a problem for you, maybe three. First, judging from your picture, it is in rock mulch. This plant will not handle a rock mulch environment very well. If it is going to work for you in rock then it should be in an eastern exposure where the wall would be to its west.

Picture will not insert properly in Blogspot. Bay Leaf of reader.
            If your plant is in this environment then it might be getting hammered by being fully exposed to the southern sun as well. It will do much better with some protection from that hot, blazing sun in the summer. That is why you are seeing the leaves with brown tips and edges.

            Secondly is the yellow color developing on the new leaves, leaves at the ends of the branches. Most likely this is a nutrient deficiency due to the poor nutrient capacity of that desert soil. Rock mulch adds nothing to a desert soil. It needs a more fertile soil and should not be planted like it is growing in the middle of a desert somewhere.

            Thirdly, you might have trouble keeping it through the winters here. It is not terribly tolerant of real low winter temperatures. If it is in the open and can get hit by cold winter winds then it may freeze back yearly or every few years when we hit a good cold spell.

            I would move it to a new location this fall, about mid-September to October. Move it somewhere where the sun won’t hammer it after noon or two PM. Heavily compost the soil when you plant it. Use organic mulch around it, not rock mulch. Put it somewhere the plant will be protected from freezing winter winds. Hope this helps.

Lack of Fullness in Japanese Blueberry

Q. I was referred to you by Lori, a Master Gardener re: my problem with my Japanese Blueberry trees. I have planted 3  in November 2009, they are about 7 ft tall, 4 ft wide, trunk column about 3 inches in diameter . Leaves seemed to fall prematurely, browning and yellowish. One of the trees bark is peeling off and appeared to be dry. I have 3 sprinkler tubes on each tree, dripping 1 gl/hr each (I think). There's no visible insects but I do not know what to find anyway. Leaves seemed scarce, does not have that fullness that other trees does.  I have not sprayed them anything, no fertilizer or some sort. I put some manure compost 2 months ago. I am a novice on gardening so my description might seem funny. I can send some pictures if that would help. I have spent so much money on them for them to die. Please help.

Japanese blueberry along a block wall in rock mulch
A. Japanese blueberries will require a soil that is a composted at the time of planting and an organic mulch on the surface of the soil after planting.  It will do terribly in south or western exposures in full sun or in rock mulches.  If you planted this Japanese blueberry from a 15 gallon container then it will require about 15 gallons of water each time you water.  

The amount of water must increase from this amount as the plant gets larger from year to year.  This can be accomplished by adding minutes to your existing irrigation schedule at each watering or adding additional emitters.  If these are 1 gallon per hour emitters and there are three of them then the irrigation run time for this tree should be somewhere around 5 hours for it to get adequate water.  

Water requirement curve for the Las Vegas area. The first bar (1) is January
and the last bar is December (12). You can see that water demand by
plants increases 400% from January to July and August.
Unless this plant is getting water from other sources it will be under watered if you are irrigating for only one are 2 hours.  The frequency of application of the water, but not the number of gallons per application, will vary from season to season.  There is generally are a winter schedule, spring schedule, summer schedule, fall schedule and back too a winter schedule which means you should increase the number of times you irrigate per week about four times each year.  

These schedules will coincide approximately with December 1, February 1, May 1, mid June, mid September and finally December 1 which completes the seasonal cycle.  

Because your plant does not have the fullness that caught your eye I would assume it is due to improper irrigation which may have led to infestation with borers.  Pull off the loose bark at you see and look for damage in the wood do too boring insects.  This would include sawdust under the bark and perhaps elliptical exit holes from the trunk under the damaged area.  If the damage is more than half way around the trunk then I would replace the plant.

Yellowing on Meyer Lemon Might Be Magnesium Deficiency

Meyer Lemon with deficiency
Q. We have went to the nursery a couple times about this tree. First we got the water cycle correct, then iron was suggested which we did as they directed then Gold Dust was suggested. Online I read possibly the tree suffers from a magnesium issue. I thought these photos would give a better picture. All we did as directed and the tree is not responding in fact it is getting worse. I am wondering if it is because of where it was planted which is a confined root growing area. Any insight would be appreciated.

Meyer lemon another shot.
A. By looking at the leaves I have to assume this is a Meyer Lemon (which is, by the way not technically a lemon but an unknown hybrid found in a Chinese back yard by USDA researcher D. Meyer in the early 20th century). Your pictures are all pretty good with the exception of not showing a critical view of the trunk where it is just out of the soil. Just for future reference always look at and show this interface of the trunk and soil. W/o that view I have to only guess that the rootstock/trunk union is well out of the soil and we can eliminate that issue. And, a shot of the soil might show how the plant is getting watered. I have to assume drippers and I would guess they are in the same locations as when the plant was planted.

The leaves show two distinctive symptoms that often occur in concert: 1. There is some salt burn and 2. The common symptom that comes with salt issues is the magnesium deficiency. Just FYI Iron def. only occurs on the new leaves.

For the salinity (salt) issue we usually look first at the watering and with watering comes knowing if the water can even be applied uniformly all around the edge of the canopy, sometimes called the 'drip line'. Citrus are botanically a shrub with shallow and wide spreading roots that are tough to grow to maturity with drippers unless they are closely spaced in a wide band around the canopy's edge. There is one picture showing the plant is right next to a step wall with no water being applied in that zone of the root system.

I would not worry too much about adding any supplements and see if you can begin to manage a watering system of application that would give a long deep soaking water application out near the drip line. The 'soaker' hoses could be laid out on the ground out near the drip line and let it run for hours and hours to try and leach out the excess salts that may have accumulated over time with the drip system. Drip systems are fine but, due to their limited water output salts can begin to accumulate thus impacting citrus' sensitivity to salts.

Give it a long deep watering about once every few weeks from now on all during the growing season (May through October)  to supplement the regular water to leach out the salts that inevitably are deposited with the limited volume of drip systems . .This leaching watering is also the great time to add fertilizer and get it into the soil evenly all around the active roots near the drip line.

Terry Mikel

Gardener Moving to Las Vegas from San Francisco

Q. My husband found your site. We are facing the possibility of a move to Las Vegas. We have never lived in a desert climate. I am hoping to continue my love of gardening with vegetables, flowers, and a water garden like I have here in the San Francisco Bay Area. My biggest problems here have been raccoons, squirrels, aphids, and powdery mildew. Will any of those be things I will face in Vegas? What are the biggest pests/problems I should prepare for? (I'm praying you don't say scorpions or fire ants!)
            Also, my great love is dahlias. I have about 44 plants here, though ironically our summer was so cool that it was a poor year for us (our tomatoes were also a disappointment, and I sure hope that won't be the case in LV). How well to dahlias fare in Vegas, and will they bloom at a different time of year? Should I consider putting them in double pots and not in the ground (we've talked about raised beds with high quality soil)? Someone told me that grasshoppers are so bad there that I will need to completely fence in the whole garden area with small mesh wire to block the bugs out, is this true? What are your thoughts?
            I realize this letter contains a lot of questions... but any help you can give a life-long gardener or who very nervous she will have to give up all the plants she loves would be greatly appreciated

A. Well Shannon... we do have bark scorpions but we don’t have very many fire ants. Those are pretty rare and relatively easy to control so far. So take a deep breath... it’s not so bad. The desert can be beautiful.

            No raccoons in the Las Vegas area. No grey squirrels but we do have ground squirrels which some call chipmunks which they aren't but they do look a little like Chip and Dale. They can be pesky.

            We do have some aphids in the spring but they disappear when it gets hot. Powdery mildew is relatively rare compared to San Francisco. Dahlias will be tough for you in Las Vegas. We can produce some wonderful vegetables and fruits here and you will find them rivaling in quality to what you can find at the Farmers Markets in San Francisco.
Ground squirrel

            Now the bad news. This is the desert. Growing things here will be NOTHING like what you are familiar with. You will have to relearn your gardening skills and adapt them to the desert climate. Your new mantra will be compost, compost, compost. And everything will revolve around water.

            Yes, you have a lot to learn but think of it as an adventure and your gardening skills will be tested here. No "throw a seed in the ground and watch it grow" here. Thats why I am here. Feel free to ask. By the way, the grasshopper story is totally far-fetched. You will need a shotgun. (Just kidding, it is not that bad ......... most years) :-)

Maybe some others here can give you some pointers.